[LAU] How to run jack at 8kHz sr?

Alessio Degani alessio.degani at ymail.com
Wed Sep 16 09:46:01 UTC 2015


Hi list,

I'm writing some signal processing algorithm for real time processing 
that has to run on a 8 kHz sampling frequency embedded device.
My code is in C and I wrote a simple jack client for testing my algorithms.
For now, I'm using a sample frequency of 44.1 kHz but I want to test the 
behaviour of my code at 8 kHz.
With my sound card, is impossible to set jack to run at 8 kHz.

It is possible in some way, to fake the 8 kHz sampling frequency (for 
example using plugins?).
I've seen the Steve Harris Decimator, but it is not designed to run in 
real time. I've tried to put in jack-rack a low-pass (antialias) filter 
followed by the SH Decimator, but the result is (as expected) a 44.1 kHz 
signal with reduced bandwith and some "aliasing" (I don't think that 
what I get is alias -by definition- but some other artifacts).

What can I do to test my algorithm at 8 kHz in realtime using jack?

Thank you all :)

-- 
a.



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